We investigated the preparation of CuIn5S8 and AgIn5S8 spinel thin films by sulphurization of Cu-In and Ag-In alloy films in sulphur vapour. We found that a good adhesion to the substrate (Mo-coated glass) could be achieved by the introduction of a Ti layer between the substrate and the spinel layer. A layer of a titanium sulphide was formed at the interface between Ti and the spinel layer. CuIn2 and AgIn2 phases in the Cu-In and Ag-In precursor alloy films and phases of cubic CuIn5S8 and AgIn5S8 spinels have been detected by X-ray diffraction. Most of the films show n-type conductivity. The electron concentration varies from the intrinsic to 10(18) cm(-3). (C) 2004 Elsevier B.V. All rights reserved.